Peter,
Thanks for the info on the book I will look into ordering it.

I have my board working but there is a problem with the EPROM programmer.

I think the AT89C52 should work programming EPROMS, I don't see why it would work differently from the 8052AH-BASIC chip, it's the sam ROM. Perhaps I've got some components wrong as I couldn't see the component overlay clearly because of poor resolution.

A bit more debugging I suspect. But the board works nicely as a BASIC computer, I like it.

Any tips on the EPROM programmer circuitry?

Peter.